Pumping plants



July 13, 1965 G. NEIDL 3,194,166

PUMPING PLANTS Filed March 21, 1963 4 Sheets-Sheet 1 F/G. f

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PUMPING PLANTS Filed Magch 2l, 1965 4 Sheets-Sheet 2 .Madam To 6 esfzrnJuly 13, 1965 G. NEIDL 3,194,166

PUMPING PLANTS Filed March 2l, 1965 4 Sheets-Sheet 5 /Nrfwrop l l Georg/F/L 356 ,/Mesm, 7ans: Meien:

July 13, 1965 G. NEIDL. 3,194,166

PUMPING PLANTS Filed March 2l, 1963 4 Sheets-Sheet 4 360 357 /NVENTOPGeary /Vf/.L

United States Patent PUMPING PLANTS Georg Neidl, Matsehils, Tresen,Furstentum, Liechtenstein Filed Mar. 21, 1963, Ser. No. 267,390 Claimspriority, application Germany, Mar. 23, 1962,

4 Claims. (Cl. 1025-87) This invention relates to a pumpingplantwherein, preferably for purposes of the submerged mounting of theentire pump, the rotor of the electrometer driving the pump body issuspended inside the stator space.k

The invention consists in that the stator containing the electricwindings is arranged together with thekwindh ings inside the casing in awater-tight manner, andthat further the bearing clearance of the topbearing, the clearance between the internal circumference of the statorand the external circumference of the rotor, and nally an annular cavitybelow the bottom bearing are all designed to be open towards the bottom,in such a manner that when the pump is sunk vertically into the liquid,to be let down to a prescribed maximum depth, under the action of thewater pressure the air present in the said spaces is only compressed tosuch an extent that merely a part of the cavity below the bottom bearingis iilled withthe entering liquid.

The plant may be provided with an oblique disc pump in which, preferablyfor purposes of installing the whole pump under water, the stator isarranged inside the casing in a water-tight manner. In such a pumpcircumferential toothing is provided on the disc and a groovearrangement is provided on the internal periphery of the pump casing.However, an oblique pump disc may be used without the provision of teethon the circumference of the disc or of grooves on the internalperipheryof the casing.

As an improvement toA and further development of the present invention,mass-produced electromotors are used which are inserted, with theinterposition of an intermediate piece, between the casing of theelectromotor and the casing of thepoblique disc pump. n

Further details of the invention are described in more detail withreference to the accompanying drawing,y in which:

FIGURE l is a vertical section through an underwater pump with dischargepipes which are kguided upwards around the casing of the pump; i v

FIGURE 2 is a top view of the pump according toy FIGURE 1 drawn to areduced scale;

FIGURE 3 is a fragmentary View of a cavity, arranged below the bottombearing of the pump, in which water FIGURE 7 is a perspective view ofthe pumping plant shown in FIG. 1; f

FIGURE 8 is a vertical section through a further modiice tied pumpingplant; and

FIGURE 9 is again a vertical section, drawn to an enlarged scale throughthe upper suspension bearing of the pump shaft of the apparatus ofFIGURE 8. y

In the embodiment shown in FIGURES 1 to 3 the rotor 300 of analternating current motor is designed as a. short-circuit armature orsquirrel-cage rotor. The rotor 300 has at its top andeits bottom arespective shaft stub 301, 302. The shaft stub 301 is mounted in aroller bearing 303, which has to take the actualweight of the armature300 and the two shaft stumps and in addition ysupports the upper shaftstump 301 in the radial direction. At the upper end of the shaft stub301 there is provided a journal 304 of smaller diameter, which ismounted in the roller bearing 303.

kThe rotor 300 is surrounded by a stator 30S, which is inserted insidethe motor casing 307 by means of pressure rings 306. The windings 308ofthe stator are connected with the stator by way of ties 309.

- .Themotor casing 307 is according to the invention, longitudinalyextended towards the top and the bottom, the free space between theystator windings 308 and the internal surface of thecasing 307 beingyoccupied by a liller material 310, which solidiies after being pouredin and encloses the stator in a water-tight and airtight manner insidethe casing. The pouring of this iiller material is preferably rstcarried out from above. Then after cooling the casing 307 is rotatedthrough and the corresponding cavity now at the top is likewise lledwith the filler material.

The upper cover 311 is then screwed onto the casing, this cover having asleeve 312 which ts so closely against the stator 308 and the shaft stub301 that only a small clearance is left between theinternal face of thesleeve 312 and the shaft stub 301. On the other hand a small space mustbe provided between the upper end of the rotor 300 and the lower endface of the sleeve 312, in order that the rotating armature does notrub. Further the cover 311 is so designed that it encloses the rollerbearing 303 as closely as possible so that the air space caused by theroller bearing is also small.

Onto the upper cover 311 is screwed a further domed cover 313 whosedomed part 314 houses a terminal box with ythe terminals for theelectric cable 315. On the domed cover there are provided eyes 316 forsuspending the machine on lowering cables. f In the lower part of thecasing 307 there is provided th-e lower cover 316 which is likewiseequipped with a sleeve 317, which encloses the lower stub 302. Thesleeve 317 has in' the upper part a bush 318, which surrounds the lowershaft stub 302 and thus supports it.

The lower end ofthe lower shaft stub 302 has oblique'- ly xed to it apump-disc body 319. c On the casing 320 there are provided,diametrically opposite one another, radially directed outlet connections321 from which by-pass discharge pipes 322 arey guided upwards, thesepipes combining above the machiney casing 307 to vform a pressuremanifold 323.

The sleeve 317'is welded below the bush 318 to form a cavity 324,through which the lower shaft stub 302 is guided. i The innergeneratrices of the two discharge connections 321 located at the upperculmination point are in alignment with the lower edge 325 of the cavity324. The cavity 324 is formed in this Way that its diameter aie/glee :'id inside the sleeve 317 is greater than the diameter c of the lowershaft stub 302.

In order that, when the machine is placed in operation, the rotortogether with the pump disc and the shaft stubs can take up a positionsymmetrically to the stator 305 inside the developing field of force, itmay be advisable to design the roller bearing 303 not simultaneously asa thrust bearing, so that upon stoppage of the machine the lower endface of the rotor 300 lies on the upper end face of the sleeve 317. Inthis case, upon starting of the machine, the rotor 300 is attracted intothe rotary field of the stator 305 and hence upwards, so that the rotoris lifted away from the end face of the lower sleeve 317.

If, according to the invention, the whole system is immersed in thefluid to be pumped, this fluid being pure water, sewage, sludge or anyother desired viscous substance, then the air present in the machinecasing 320 can escape via the two discharge connections 321 and thedischarge pipes 322 (shown in dotted lines) into the coinmon, verticalcollecting pipe 323. Hence the level of the material being pumped istheoretically fixed at the level of the edge 325. According to the depthof sinking of the pumping plant and hence according to the extent of theexcess pressure, the water level 326 will rise within the cavity 324, asshown in FIGURE 3, and by selecting the size of the individual airspaces `one can achieve the result that with a maximum immersion depth,there is still an air space below the lower end face of the bush 313, sothat the bush is not surrounded by fluid.

These conditions will be explained in more detail hereinafter by meansof a numerical example:

Let it be assumed that the external diameter a of the rotor 300 amountsto 120 mm., whilst the internal diameter b of the stator 305 amounts to121 mm. Then there is present between the rotor 300 and the stator 305an air space of 0.5 mm. The length of the armature 300 is shown inFIGURE 1 at e and should be 200 mm. The diameter of the lower shaft stub302 is designated c and should amount to 3,0 mm., whilst the internaldiameter d of the cavity 325 is 40 mm. The length of the cavity 325 isdesignated f and is 150 mm.

Let it be assumed further that the air volume of the free space insidethe roller bearing 303 including the volume of the annular gap betweenthe shaft stub 301 and the cover 311 Vamounts to 10 cc. The air volumeof the annular space between the armature and the stator is calculatedas follows: The surface area of the entire stator cavity is calculatedaccording to the formula 1r/4-1212 with a diameter of 121 mm. -at 115cm2. From this must be deducted the surface area of the rotor which witha diameter of 120 mm. amounts to 113.1 cm2. The difference between thesaid surface areas gives the surface area of the annular gap=1.9 cm2.The volume of the annular gap then amounts, with the length e of 200mm., to 1.920=38 cc.

The surface area of the cavity 324 is caljlated from Ithe 12.5 cm.2surface area corresponding tol diameter :1:40 mm. minus the surface areaof the shaft stub corresponding to its diameter :30 mm. and amountingto7.l cm?. The difference inthe surface areas at 5.4 cm.2 gives thecross-section of the annular cavity 324, the volume of which with f=150mm. length is approximately 81 cc.

If the whole unit is immersed in the fiuid, then with an immersion depthof the magnitude zero, with respect to the lower'edge 325, the fluidlevel of the immersion material would be at the lower level 325. On theother hand, if the unit is immersed to a depth of m., then the immersedmaterial, with an excess pressure of 10 m. head of liquid, and with anassumed specific weight of the immersion material of 1, penetrates viathe annular surface 325 into the cavity 324 designated as a bufferchamber.

In .order to calculate this depth of penetration, we will start for thesake of simplification from a isothermal compression, for which thefollowing formula applies: p1V1=p2-V2- Here p1 designates the pressurebefore the immersion=l.0 absolute pressure in atmospheres, whilst p2=2.0absolute pressure in atmospheres, i.e. the iiuid pressure afterimmersion which acts in an upward direction against the annular surface325 into the buffer space 324. V1 constitutes 4the sum of three volumes,i.e., the air space or volume of the bearing 303:10 cc., that of the gapbetween stator and rotor amounting to 38 cc. and that of the bufferchamber 324:81 cc. Finally V2 designates the reduced volume which occursas a result of the pressure p2. Accordingly the following equationapplies after the immersion:

Thus V2=130/2 or V2=65 cc.

Naturally the volume of the roller bearing 303 remains unchanged at l()cc. as also does the stator gap with 38 cc. This results in a volume fof48 cc. As, however, according to the calculation, the total volume stillonly amounts to 65 cc., then the free volume in the buffer chamber 324is reduced 'to 65 minus 48, i.e. 17 cc.,.so that, as shown in FIGURE3, water level 326 has risen in the annular cavity 324 to such an extentthat a volume of 17 cc. remains between the lower face of the bush 318and the water level 326. As the annular chamber 324 has a cross-sectionof 5.4 cc., the level h according to FIGURE 3 is reduced tol7+5.4=approximately 3 cm., whilst'in the first instance according toFIGURE 1, the level h amounted to 15 cm. In this calculation the annulargap between the lower shaft stub 302 and the bush 318 has beendisregarded for the sake of simplicity.

It can be seen from the above that at an immersion depth of 10 m. thewater cannot penetrate into the elec-v tromotor at all, because theelectromotor is a filled motor with respect to its stator and rotor andsecondly the lower bush 31S is not even in contact with the water.

The intermediate ring 327 designated in FIGURE 1 constitutes asimple'inventive means for lengthening the cavity 324, in order toobtain suitably prescribed immersion depths with certainty so that thewater level does not reach the lower annular surface of the bush 318.The dimension f can thus be increased within certain limits. By thismeans notonly the bush 318 but also the entire electromotor can be keptdry. One can also increase the diameter d of the cavity 324 in relationto thel diameter c of the lower shaft stub 302 and have thuspossibilities of increasing the buffer-chamber volume in bothdirections.

In order to keep the unit as light as possible, the sleeve 312 of thecover 311 can, as shown in FIGURE 6, be provided with cavities 328.

According to the embodiment of FIGURE 4 there are provided instead ofthe discharge pipes 322.0f FIGURE 1, the design of the pumping plantbeing otherwise the same, apertures 329 in the upper terminal wall ofthepump casing 320, so that the fluid sucked up enters through theseapertures an annular chamber`330 provided outside the motor casing 307,this chamber being formed by the provision of a hood 331 round the motorcasing 307 tapering upwardly and opening into the discharge pipe 323. Inthis embodiment the current cable 315 is guided through a bore inthehood and protected from penetration of water by a packing 332. Thecarrying eyes 333 are in this embodiment secured to the hood 331.

As shown in the sectional view of FIGURE 5, not only two diametricallyopposite apertures 329, but also additional openings 334 are provided inthe pump-casing cover 320. Finally, in order to have a particularlylarge transition cross-section, an annular aperture 335 may be providedin the upper casing cover as illustrated in dotted lines. The hood 331is secured by means of a flange 336 to the pump casing 320.

invention can also be used for pumps of normal design,

that is to say for pumps wherein the pump rotor is not an oblique discpump but, for example, a centrifugal pump impeller.

The filler mass 310 as shown in FIGURE 1 can also be used at the sametime to till the intermediate spaces between the individual groups ofwindings 3dS. In this connection it may be expedient to use for the llermass a material which has good heat conductivity in order to divertsuliciently outwardly the joulean heat generated.

Although the lower bush 31S is, according to the invention, not wettedby the water to be pumped, it may nevertheless be advantageous incertain cases to provide a stuffing-box packing on this bush 318, sothat a waterand moisture-repellent closure is obtained. y yThe unitaccording to the invention is, in 'contradistinction to knownconstructions, in full equilibrium, i.e. the unit never hangs askew,which is due particularly to the fact that the outflow of the liquidbeing pumped takes place by way of fully symmetrical outlet'openings andoutlet pipes. i y

rFrom the perspective view in FIGURE 7 one can particularly clearly seethe method of connecting the electric cable 315 and the form of thewhole unit.

According to the embodiment shown iny FIGURES 8 and 9 the mass-producedelectromotor 35!) is simply connected to the oblique disc pump 351 withthe aid of an intermediate piece 352, without any special adaptation ofthe casing of the electromotor. The lower cover 353 is Iscrewed onto theflange 355 of the intermediate piece by anchor screws 354. Between thelower motor cover 353 and the upper side 356 of the intermediate piece352 there is preferably poured an insulating composition 357 and thisintermediate space is thus lled and therefore has as little air aspossible particularly in the vicinity of the rotating parts of themachine shaft 358. The intermediate piece 352 has an annular space 359,in which the air is compressed by penetration of water when the pump islowered.

If such a plant is used for example as a dredger for pumping out, thenthe machines at the end of the dredging operation, usually therefore atnightfall, are lifted out of the water whilst the plant idles.Accordingly the annular space 359 can lill with fresh air again. It isdifferent in a plant, for example, which is intended to be used as asewage-pumping mechanism. This is sunk permanently in the sewage sump.In such a case, in modification of the inventive idea, on reaching of acertain maximum sewage level inthe sewagesump, the circulating pump isautomatically switched on exactly as when using normal pumps. On theother hand the stopping water level, that is to say the water level atwhich the machine automatically stops pumping, should not generally fallbelow the lowest edge 360 of the machine, because otherwise air issucked through the machine in an undesirable manner. Generally such amachine is then switched olf when the sewage just covers the lower partof the pump casing. This ensures that the pump contains no air pocketswhen the water level sinks. Otherwise the machine would begin to spinand accordingly cease or almost cease to pump.

During tests on the test stand it has been ascertained that the machineaccording to the invention pumps completely empty, that is to say rightup to its lowermost edge, Without spinning. This undesirable spinningonly takes place when the water level sinks below the bottom edge 360.In order to avoid this, there is used according to the invention astopping electrode or a stopping float arrangement which switches on aretarding relay as soon as the water level has sunk to the upper edge361 of the circulating pump. This relay establishes a slowing-down timeof the circulating pump which can be set by hand. During thisslowing-down time, the water level sinks to the lower yedge 360 of themachine. At this moment frothing occurs between the sewage and the air,i.e. air enters the machine casing 362. Only then does the machine stopafter release of the relay.

By using such a retarding relay one ensures that the circulating pumpand hence also the air space 359 can again fill with fresh air. n

The air space inside the electrornotor is, in the design yaccording tothe invention, so small that even when water does penetrate this smallair space inside the electromotor, this water is evaporated on accountof its small quantity in the shortest possible time by the heat producedby the running electromotor. The electromotor then runs withoutdisturbance, except that its power factor, is increased or its elhciencysomewhat reduced. This however is of `no importance in coarse underwateroperation, e.g., in dredgers, for pumping out ponds and the like.

lf the motor is switched oif and remains under water, then the watervapor condenses and water again penetrates the electromotor. At the nextswitching on the abovedescribed operation is repeated.

lf the motor is taken out of the water after being switched off, thenthe water runs out of the motor again. In the latest electromotors thelacquerfor the windings and other parts of the electrornotor is of suchhigh quality that penetration of water is to a certain extent harmless.Therefore, owing to the small extent of the empty spaces located in themotor, the penetration ofthe water is of no importance. ln thisconnection the water by no means needs to penetrate so far into themotor that the latter is filled right up to the top with water. Thus ismay happen that only as much water penetrates from below into theelectromotor as to Ilill the latter half or three-quarters with water.Even when, through the intensive external cooling of the electromotorimmersed in the water or sewage, the water which has penetrated theelectromotor does not evaporate, it is only a question of suchsmallquantities that the machine continues to work without disturbance. Heatis consumed bythe evaporation of the water or liquid in the filledelectromotor. This favors at the same time internal cooling of themachine in an advantageous manner. The ywater vapor formed Linside thelled motor may, in accordance with the inventive idea, be considered lasa gas under pressure, which offers resistance to the penetration of thewater from below. If condensation of the water vapor to water againoccurs through cooling of the motor owing to a fairly long switching-ottperiod, then the evaporation procedure is repeated yafter theelectromotor is switched on.

I rclaim: f l. A totally submersible pumping plant comprising firsthousing means centered on a vertical axis; an electromotor in said lirsthousing means having a downwardly extending vertical shaft journaledcoaxially therein and carrying an armature received with peripheralclearance in said iirst housing means;

an impeller cantilever mounted at a lower extremity of said shaft forrotation about said axis thereby;

second housing means surrounding said impeller and forming a downwardlyopen pumping chamber' therearound, said second housing means beingformed with at least one generally radial outlet communicating with saidchamber;

means forming an air compartment interconnecting said clearance and saidchamber, said compartment constituting substantially the sole fluidcommunication with said clearance;

and bearing means interposed between said iirst housing means and saidshaft at the junction between said compartment and said clearance, theair-enclosing volumes of said clearance and said compartment beanotarseing so selected that, upon submersion of said pumping plant in anupright condition, the air within said clearance and said compartment iscompressed and prevents entry of liquid into said iirst housing meansthrough said compressor beyond said bearing means.

2. A totally submersible pumping plant comprising:

irst housing means centered on a vertical axis;

an electromotor spacedly disposed in said tirst housing means andforming an annular conduit chamber therewith, said electromotor having adownwardly extending vertical shaft journaled coaxially in said Iirsthousing means and carrying an armature received with peripheralclearance;

an impeller cantilever mounted at a lower extremity of said shaft forrotation about said axis thereby;

second housing means surrounding said impeller and forming a downwardlyopen pumping chamber therearound, said second housing means being formedwith at least one generally radial outlet communicating between saidpumping chamber and said conduit chamber;

means forming an air compartment interconnecting said clearance and saidpumping chamber, said compartment constituting substantially the solefluid communication with said clearance;

and bearing means interposed between said irst housing means and saidshaft at the junction between said compartment and said clearance, theair-enclosing volumes of said clearance and said compartment being soselected that, upon submersion of said pumping plant in an uprightcondition, the air within said clearance and said compartment iscompressed and prevents entry of liquid into said first housing meansthrough said compartment beyond said bearing means.

3. A totally submersible pumping plant comprising:

iirst housing means centered on a vertical axis;

an electromotor in said irst housing means having a downwardly extendingvertical shaft journaled caxially therein and carrying an armaturereceived with peripheral clearance in said iirst housing means;

an impeller disk cantilever mounted at a lower extremity of said shaftat an angle thereto for rotation about said axis thereby and generationof a generally cylindrical surface by the periphery of said disk.

second housing means surrounding said impeller disk and forming adownwardly open substantially cylindrical pumping chamber therearound,said second housing means being formed with at least one generallyradial outlet communicating with said chamber;

means forming an air compartment interconnecting said lclearance andsaid chamber, said compartment constituting substantially the sole uidcommunication with said clearance;

and bearing means interposed between said lirst housing means and saidshaft at the junction between said compartment and said clearance, theair-enclosing volumes of said clearance and said compartment being soselected that, upon submersion of said pumping plant in an uprightcondition, the air within said clearance and said compartment iscompressed and prevents entry of liquid into said rst housing meansthrough said compartment beyond said bearing means.

4. A totally submersible pumping plant comprising:

first housing means centered on a vertical axis;

an electromotor spacedly disposed in said iirst housing means andforming an annular conduit chamber therewith, said electromotorV havinga downwardly extending vertical shaft journaled coaxially in said irsthousing means and carrying an armature received with peripheralclearance;

an impeller disk cantilever mounted at a lower extremity of said shaftat an angle thereto for rotation about said axis thereby and generationof a generally cylindrical surface by the periphery of said disk;

second housing means surrounding said impeller disk and forming adownwardly open substantially cylindrical pumping chamber therearound,said second housing means being formed with at least one generallyradial outlet communicating between said pumping chamber and saidconduit chamber;

means forming an air compartment interconnecting said clearance and saidpumping chamber, saidcompartment constituting substantially the solefluid communication with said clearance;

and bearing means interposed between said iirst housing means and saidshaft at the junction between said compartment and said clearance, theair-enclosing volumes of said clearance and said compartment being soselected that, upon submersion of said pumping plant in an uprightcondition, the air within said clearance and said compartment iscompressed and prevents entry of liquid into said irst housing meansthrough said compartment beyondA said bearing means.

References Cited by the Examiner UNITED STATES PATENTS 2,764,943 10/56Peters 103-87 2,839,006 6/58 Mayo 103-87 2,918,016 12/59 Olson 103--873,013,500 12/61 Bollinborn et al 103-87 3,041,976 7/62 Maynard 103--87FOREIGN PATENTS 77,426 4/18 Switzerland.

LAURENCE v. EFNER, Primary Examiner.

ROBERT M. WALKER, Examiner.

1. A TOTALLY SUBMERSIBLE PUMPING PLANT COMPRISING FIRST HOUSING MEANSCENTERED ON A VERTICAL AXIS; AN ELECTROMOTOR IN SAID FIRST HOUSING MEANSHAVING A DOWNWARDLY EXTENDING VERITICAL SHAFT JOURNALED COAXIALLYTHEREIN AND CARRYING AN ARMATURE RECEIVED WITH PERIPHERAL CLEARANCE INSAID FIRST HOUSING MEANS AN IMPELLER CANTILEVER MOUNTED AT A LOWEREXTREMITY OF SAID SHAFT FOR ROTATION ABOUT SAID AXIS THEREBY; SECONDHOUSING MEANS SURROUNDING SAID IMPELLER AND FORMING A DOWNWARDLY OPENPUMPING CHAMBER THEREAROUND, SAID SECOND HOUSING MEANS BEING FORMED WITHAT LEAST ONE GENERALLY RADIAL OUTLET COMMUNICATING WITH SAID CHAMBER;